Use of Legacy Authentication Protocols in Azure AD

SigmaHQ Detections@sigmaHQ

•updated Oct 23, 2025•1•0•44

This rule detects the use of legacy authentication protocols for sign-ins to Azure AD. Legacy authentication protocols (such as POP3, IMAP, SMTP, MAPI, Exchange ActiveSync, Exchange Web Services, and 'Other client') do not support modern security features like Multi-Factor Authentication (MFA) and are often targeted by attackers for credential stuffing, brute-force attacks, and other credential-based attacks. Detecting and alerting on these sign-ins helps identify potential compromise or policy violations.